code: def expected_y_stat_l(geom):
      return dict(geom=geom, margin_side="l", marginal=True, x=0)
  
file_path: lets-plot/python-package/test/plot/test_marginal_layer.py
imports: import pytest
  import lets_plot
label_desc: Use image node_id 3 for calling a global function with example usage: expected_y_stat_l(geom) and returns: dict